Connectors for use in systems and methods for reducing the risk of proximal junctional kyphosis

ABSTRACT

Systems and methods for reducing the risk of PJK, PJF, and other conditions are disclosed herein. In some embodiments, a longitudinal extension can be added to a primary fixation construct to extend the construct to one or more additional vertebral levels. The extension can be attached to a first attachment point, such as a spinous process of a vertebra that is superior to the primary construct. The extension can also be attached to a second attachment point, such as a component of the primary construct or an anatomical structure disposed inferior to the first attachment point. The extension can be more flexible than the primary construct and/or can limit motion to a lesser degree than the primary construct, thereby providing a more-gradual transition from the instrumented vertebrae to the natural patient anatomy adjacent thereto. The extension can be placed with little or no soft tissue disruption.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/663,865, filed Jul. 31, 2017, which is hereby incorporated byreference in its entirety.

FIELD

Systems and methods for reducing the risk of proximal junctionalkyphosis (PJK), proximal junctional failure (PJF), and other conditionsare disclosed herein.

BACKGROUND

There are a number of spinal surgeries in which a fixation orstabilization construct is implanted in a patient and attached to thepatient's spine. For example, a typical posterior fixation construct mayinclude one or more longitudinal spinal rods attached to multiple of thepatient's vertebrae by respective bone anchors. Exemplary bone anchorscan include pedicle or lateral mass screws, hooks, wires, and so forth.The implanted construct extends along a segment of the spine between anuppermost instrumented vertebra (UIV), i.e., the most-superior ormost-cranial vertebra to which the construct is attached, and alowermost instrumented vertebra (LIV), i.e., the most-inferior ormost-caudal vertebra to which the construct is attached.

One complication that can arise with these surgeries is an undesireddegree of kyphosis at or above the UIV. Proximal junctional kyphosis(PJK) is typically defined as a proximal junctional sagittal Cobb anglegreater than 10 degrees, or at least 10 degrees greater than in apre-operative measurement. It is estimated that between 5% and 46% ofadult spine patients suffer from some form of PJK, with most cases beingdiagnosed weeks or months after the surgery. In some cases, proximaljunctional failure (PJF) can occur. PJF may be characterized by (i)post-operative fracture of the UIV or the vertebra superiorly-adjacentthereto (UIV+1), (ii) UIV implant failure, (iii) PJK increase greaterthan 15 degrees, and/or (iv) a need for proximal extension of the fusionor the construct within 6 months of the surgery. FIG. 1 is a sagittalview of a patient spine S in which PJK/PJF has occurred above the UIVafter surgery to implant a fixation construct C. Patients who sufferfrom PJK or PJF may experience increased pain, neurologic deficit, orambulatory difficulties, and may be faced with revision surgery and theexpenses and risks associated therewith.

SUMMARY

Systems and methods for reducing the risk of PJK, PJF, and otherconditions are disclosed herein. In some embodiments, a longitudinalextension can be added to a primary fixation construct to extend theconstruct to one or more additional vertebral levels. The extension canbe attached to a first attachment point, such as a spinous process of avertebra that is superior to the primary construct. The extension canalso be attached to a second attachment point, such as a component ofthe primary construct or an anatomical structure disposed inferior tothe first attachment point. The extension can be more flexible than theprimary construct and/or can limit motion to a lesser degree than theprimary construct, thereby providing a more-gradual transition from theinstrumented vertebrae to the natural patient anatomy adjacent thereto.The extension can be placed with little or no soft tissue disruption.

In some embodiments, a surgical method can include attaching a primaryconstruct to a spine of a patient, the primary construct extendingbetween an uppermost instrumented vertebra (UIV) and a lowermostinstrumented vertebra (LIV); attaching a connector to a first attachmentpoint, the first attachment point comprising a spinous process disposedsuperior to the UIV of the primary construct; positioning the connectorrelative to the patient's spine; and attaching the connector to a secondattachment point, the second attachment point being disposed at orinferior to the UIV of the primary construct.

The first attachment point can include a plurality of spinous processesdisposed superior to the UIV of the primary construct. The secondattachment point can include first and second spinal rods of the primaryconstruct. The second attachment point can include first and second boneanchors of the primary construct. The connector can include a main bodywith first and second arms extending in a superior direction therefrom.Attaching the connector to the second attachment point can includeattaching opposed connection points of the main body to contralateralcomponents of the primary construct. The arms can be curved in thesagittal plane and can apply extension forces to the patient's spine.Attaching the connector to the first attachment point can include urgingteeth formed on the arms into engagement with the spinous process.Attaching the connector to the first attachment point can includepositioning first portions of each arm in contact with respectivelateral surfaces of the spinous process and positioning second portionsof each arm in contact with a superior surface of the spinous process.Attaching the connector to the first attachment point can includesuturing or riveting the arms of the connector to the spinous process.Attaching the connector to the first attachment point can includeapplying sutures through apertures formed in the arms. Positioning theconnector relative to the patient's spine can include at least one of:(i) longitudinally translating the arms relative to the main body withinrecesses formed in the main body and (ii) tilting the arms relative tothe main body within recesses formed in the main body. Positioning theconnector relative to the patient's spine can include tightening alocking mechanism of the connector to lock a position and/or orientationof the arms relative to the main body. Positioning the connector caninclude spreading the arms of the connector apart from one another toallow the spinous process to be inserted therebetween and then returningthe arms towards one another to capture the spinous process within aspace defined between the arms.

Attaching the connector to the first attachment point can includerotating or sliding a collar with respect to the arms of the connectorto clamp the arms onto the spinous process. The arms can have astiffness that is greater than a stiffness of patient anatomy superiorto the UIV of the primary construct and that is less than a stiffness ofthe primary construct. The arms can have a degree of spinal motionrestriction that is greater than that of patient anatomy superior to theUIV of the primary construct and less than that of the primaryconstruct. The arms can limit flexion of the spine without completelypreventing such flexion. The primary construct can be implanted througha primary incision and the connector can be positioned relative to thepatient's spine and attached to the first and second attachment pointsthrough the primary incision. The primary incision can have a superiorterminal end that is disposed at or inferior to the UIV of the primaryconstruct. Positioning the connector relative to the patient's spine caninclude tunneling first and second arms of the connector in a superiordirection from the primary incision to position the arms alongside aplurality of spinous processes disposed superior to a superior terminalend of the primary incision. Attaching the connector to the secondattachment point can include threading an elongate flexible tetherthrough one or more apertures of the connector and attaching the tetherto the primary construct. In some embodiments, vertebrae instrumentedwith the primary construct are fused to one another or prepared for suchfusion and vertebrae to which the primary construct is extended by theconnector are not fused or prepared for fusion. The primary constructcan include a rigid spinal rod attached to first and second vertebrae byrespective bone anchors. In some embodiments, no portion of theconnector is disposed anterior to any lamina of the patient's spine whenthe connector is attached to the first and second attachment points.

In some embodiments, a surgical system can include a primary constructcomprising a rigid spinal fixation rod and first and second bone anchorsconfigured to attach the spinal rod to first and second vertebrae; and aconnector comprising: a main body having at least one attachment pointfor attaching the connector to the primary construct; and first andsecond arms extending in a superior direction from the main body.

The at least one attachment point can include first and second rodreceiving recesses disposed at opposite ends of the main body. The mainbody can include a transverse strut extending between the first andsecond rod receiving recesses. The first and second arms can extendsuperiorly from the transverse strut. The arms can include bone engagingteeth or surface features formed thereon. The arms can be shaped to wraparound the superior edge of a spinous process. The arms can be shaped tosimultaneously contact a lateral surface of a spinous process and asuperior surface of said spinous process. The arms can be selectivelytranslatable and/or rotatable relative to the main body. The main bodycan include a locking mechanism configured to lock a position and/ororientation of the arms relative to the main body. The arms can be moreflexible than the spinal rod. The arms can extend superiorly from themain body by a length of at least two vertebral levels of an adult humanpatient. The arms can include apertures for receiving a fastenertherethrough. The arms can merge into a single arm as they approach themain body. The system can include a collar that is rotatable and/orslidable relative to the arms to move the arms towards one another. Thecollar can include an interior thread engaged with an exterior thread ofthe arms, at least one of the interior and exterior threads beingtapered. The system can include an elongate flexible tether insertablethrough one or more openings formed in the main body of the connector.The main body can include one or more locking elements configured toclamp onto the tether when the tether is disposed through the one ormore openings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sagittal view of the spine of a human patient suffering fromPJK/PJF;

FIG. 2A is a perspective view of a human spine with a primary constructand a longitudinal extension attached thereto;

FIG. 2B is a flow chart of a surgical method;

FIG. 3 is a perspective view of a connector attached to a patient'sspine;

FIG. 4 is a perspective view of another connector attached to apatient's spine;

FIG. 5 is a top view of another connector attached to a patient's spine;

FIG. 6 is a top view of another connector attached to a patient's spine;

FIG. 7 is a top view of another connector attached to a patient's spine;

FIG. 8 is a top view of another connector attached to a patient's spine;

FIG. 9 is a perspective view of another connector attached to apatient's spine;

FIG. 10 is a perspective view of another connector attached to apatient's spine;

FIG. 11 is a perspective view of another connector attached to apatient's spine; and

FIG. 12 is a top view of another connector attached to a patient'sspine.

DETAILED DESCRIPTION

Systems and methods for reducing the risk of PJK, PJF, and otherconditions are disclosed herein. In some embodiments, a longitudinalextension can be added to a primary fixation construct to extend theconstruct to one or more additional vertebral levels. The extension canbe attached to a first attachment point, such as a spinous process of avertebra that is superior to the primary construct. The extension canalso be attached to a second attachment point, such as a component ofthe primary construct or an anatomical structure disposed inferior tothe first attachment point. The extension can be more flexible than theprimary construct and/or can limit motion to a lesser degree than theprimary construct, thereby providing a more-gradual transition from theinstrumented vertebrae to the natural patient anatomy adjacent thereto.The extension can be placed with little or no soft tissue disruption.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the systems and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the systems andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments.

FIGS. 2A-2B schematically illustrate a system and method for treating,preventing, or reducing the risk of proximal junctional kyphosis,proximal junctional failure, and other conditions. As shown, a primaryconstruct 200 can be implanted in a patient and attached to thepatient's spine S. The primary construct 200 can be extended to one ormore additional vertebral levels by (i) attaching a longitudinalextension 202 to a first attachment point 204, (ii) positioning thelongitudinal extension relative to the patient's spine, and (iii)attaching the longitudinal extension to a second attachment point 206.The first attachment point 204 can be an implant or an anatomicalstructure that is longitudinally offset from the primary construct 200,e.g., one or more vertebral levels superior to the UIV of the primaryconstruct. The extension 202 can be attached to the first attachmentpoint 204 in a manner that does not disrupt or only minimally disruptssoft tissue in the vicinity of the first attachment point. The secondattachment point 206 can be an implant or an anatomical structuredisposed at or below the UIV of the primary construct 200. For example,the second attachment point can be a rod 208, bone anchor 210, or othercomponent of the primary construct 200 itself, or a vertebra to whichthe primary construct is attached. The above steps can be performed inany sequence. For example, the extension 202 can be implanted prior tothe primary construct 200. As another example, the extension 202 can beattached to the first attachment point 204 after placing the extensionin its final position relative to the spine and/or after attaching theextension to the second attachment point 206.

The extension can provide a step-down in stiffness and/or spinal motionrestriction between the primary construct (which is typically relativelyrigid and immobile) and the natural soft tissue and other patientanatomy superior to the primary construct (to which there is generallyno implant-based rigidity or mobility restriction applied). Theextension can have a stiffness that is greater than the natural patientanatomy and less than the primary construct. The extension can have adegree of spinal motion restriction that is greater than the naturalpatient anatomy and less than the primary construct. The extension canhelp insulate the patient anatomy superior to the primary construct fromforces and stress that may contribute to PJK/PJF. The extension canprovide a soft link between the primary construct and undisturbed softtissue superior thereto. The extension can constrain or limit flexion ofthe spine to reduce the risk of PJK/PJF. The extension can replicate thenatural soft tissue envelope. In some embodiments, the vertebraeinstrumented with the primary construct are fused to one another and thevertebrae to which the primary construct is extended by the extensionare not fused. Accordingly, a hybrid construct can be formed in which afirst spinal segment is instrumented and fused, a second spinal segmentsuperior to the first segment is instrumented and not fused, and a thirdspinal segment superior to the second segment is neither instrumentednor fused.

Referring now to FIG. 2B, in a step S1, a primary construct can beimplanted in the patient. The primary construct can include one or morespinal rods extending longitudinally along the patient's spine. Thespinal rod or rods can be attached to the patient's spine using boneanchors such as pedicle or lateral mass screws, hooks, wires, and soforth. The primary construct can extend along a segment of the spinebetween an uppermost instrumented vertebra (UIV) of the primaryconstruct, i.e., the most-superior or most-cranial vertebra to which theprimary construct is attached, and a lowermost instrumented vertebra(LIV) of the primary construct, i.e., the most-inferior or most-caudalvertebra to which the primary construct is attached. The UIV can be theuppermost vertebra in which a bone screw of the primary construct isimplanted. The LIV can be the lowermost vertebra in which a bone screwof the primary construct is implanted. The primary construct can beimplanted using any of a variety of known techniques, including openprocedures, minimally-invasive or percutaneous procedures, and so forth.The primary construct can be implanted through a primary incision. Theprimary incision can extend longitudinally along the patient's spine.The terminal superior end of the primary incision can be locatedinferior to UIV+1, inferior to UIV, and/or inferior to UIV−1. Theprimary incision can include a plurality of discrete incisions, e.g., inthe case of minimally-invasive procedures for installing the primaryconstruct. The primary construct can include a rigid spinal rod, e.g., arod that does not materially bend or deform post-implantation whensubjected to normal anatomical loads, or a rod which is not designed tobend or deform under such conditions.

In a step S2, a longitudinal extension can be attached to a firstattachment point, e.g., a location within the patient that is offsetfrom the primary construct. The extension can be or can include any of avariety of elements for extending the primary construct to one or moreadditional vertebral levels. For example, the extension can be a tether,cable, cord, mesh, fabric, tape, film, or wire. The extension can beflexible. The extension can have a stiffness that is less than that ofthe primary construct or a component thereof, e.g., less than astiffness of a spinal rod of the primary construct. The extension canhave a stiffness that is greater than that of the natural spinalanatomy, e.g., greater than that of the ligaments and other soft tissuethat connect the vertebrae.

The extension can be connector of the type described below. Theextension can be a length of MERSILENE tape available from ETHICON ofSomerville, N.J. The extension can be a length of non-absorbable,braided, sterile material. The extension can be formed from poly(ethylene terephthalate). The extension can be formed from fibers ofhigh molecular weight, long-chain, linear polyesters having recurrentaromatic rings. The extension can be coated with anti-bacterial agents,corticosteroids, anti-infective agents, tryclosan, and so forth. Theextension can be radiopaque, radiolucent, or partially radiopaque andpartially radiolucent. The extension can include imaging bands ormarkers. The extension can be polymeric. The extension can be formedfrom or can include various materials including polyethyleneterephthalate or DACRON, polytetrafluoroethylene or TEFLON,poly-paraphenylene terephthalamide or KEVLAR,ultra-high-molecular-weight polyethylene (UHMWPE), nylon, poly(L-lacticacid), and the like. The extension can be reinforced with materialsincluding metals, elastomers, carbon fibers, etc. The extension caninclude resilient or shape memory materials such as elastomers ornitinol. Such materials can allow the extension to not only limitflexion of the spine, but also to instill extension forces, which mayimprove lordosis and/or reinforce posterior soft tissues. The extensionforces can be tailored based upon material properties, weavingstructure, thickness, or other attributes of the extension.

The extension can be a tether that is substantially flat or planar. Thetether can have a cross-sectional width that is greater than across-sectional height. For example, the width can be at least two timesgreater than the height. The width of the tether can be in the range ofabout 4 mm to about 8 mm. The height of the tether can be in the rangeof about 0.5 mm to about 2.5 mm. The tether can have any number ofdifferent cross-sections, including rectangular, square, elliptical,circular, and so forth.

The extension can be attached to a first attachment point that is offsetfrom the primary construct, e.g., one or more vertebral levels superiorto the primary construct. The first attachment point can be a vertebra.The first attachment point can be a pedicle, a transverse process, alamina, a facet, a spinous process, or a vertebral body of the vertebra.The first attachment point can be an implant implanted in any of theabove locations. The vertebra can be superior to UIV. The vertebra canbe UIV+1, UIV+2, or higher. The first attachment point can be a rib orother anatomical anchor point. The first attachment point can be a bonestructure. The first attachment point can be a soft tissue structure.The first attachment point can be a muscle, a tendon, or a ligament. Theextension can be attached to a plurality of the above-described firstattachment points.

The extension can be attached to the first attachment point in any of avariety of ways. The extension can be attached to the first attachmentpoint using a suture, rivet, or staple. The extension can be attached tothe first attachment point using a clamp. The clamp can be attached to alamina, spinous process, or other anatomical structure or implant. Theextension can be attached to the first attachment point using a hook.The hook can be hooked onto a lamina, spinous process, or otheranatomical structure or implant. The extension can be attached to thefirst attachment point using a bone anchor, e.g., a screw anchor, asuture anchor, an expandable anchor, a tether anchor, and/or asoft-tissue anchor, any of which may be of the type available from DEPUYSYNTHES of Raynham, Mass.

The extension can be attached to the first attachment point in a waythat minimizes soft tissue disruption. The extension can be positionedat the first attachment point without extending the primary incisionand/or without forming any incision other than the primary incision. Theextension can be positioned at the first attachment point through asmall secondary incision formed over the first attachment point. Thesecondary incision can be percutaneous stab incision. The secondaryincision can be made only as large as necessary to pass the extensiontherethrough, or only as large as necessary to pass an anchor forattaching the extension therethrough. The secondary incision can have alength that is equal or substantially equal (e.g., within 10% of) acorresponding dimension of the extension. The secondary incision canhave a diameter that is equal or substantially equal (e.g., within 10%of) a diameter of a bone anchor used to attach the extension to thefirst attachment point. The secondary incision can have a length ordiameter that is less than about 10 mm, less than about 5 mm, less thanabout 3 mm, and/or less than about 1 mm. The extension, or at least oneend thereof, the anchor, or both the extension and the anchor, can bedelivered to the first attachment point through a trocar, tube, orcannula. The extension can be attached to the first attachment pointwithout disturbing the soft tissue envelope of the vertebral levelssuperior to the primary construct.

In a step S3, the extension can be positioned relative to the patient'sspine. The extension can be positioned to extend along the patient'sspine between the first attachment point and a second attachment point,such as the primary construct.

The extension can be passed through the secondary incision and thenpushed and/or pulled in an inferior direction towards the primaryconstruct, passing the extension beneath the skin and/or soft tissuedisposed intermediate to the secondary incision and the primaryconstruct. The extension can be pushed and/or pulled in the inferiordirection by an inserter or tunneling instrument. The inserterinstrument can be passed through the primary incision and up towards thesecondary incision to grab the extension before pulling it inferiorly.The inserter instrument can be passed through the secondary incision andpushed with the extension coupled thereto inferiorly towards the primaryconstruct, beneath the skin and/or soft-tissue.

The extension can be inserted through the primary incision and passed ina superior direction towards the first attachment point, guiding theextension beneath the skin and/or soft tissue disposed intermediate tothe first attachment point and the primary incision. The extension canbe passed in the superior direction using forceps, a pushrod, or otherinserter instrument.

The extension can be positioned along a posterior aspect of the spine.The extension can be positioned along an anterior or lateral aspect ofthe spine. The extension can be positioned such that no portion of theextension is disposed anterior to any lamina of the patient's spine.

The extension can be positioned in a way that minimizes soft tissuedisruption. The extension can be positioned without extending theprimary incision and/or without forming any incision other than theprimary incision. The extension can be positioned without disturbing thesoft tissue envelope of the vertebral levels superior to the primaryconstruct.

In a step S4, the extension can be attached to a second attachmentpoint. The second attachment point can be inferior to the firstattachment point. The second attachment point can be a spinal rod, abone anchor or bone screw, a cross-connector, or any other component ofthe primary construct. The second attachment point can be an anatomicalstructure adjacent or inferior to the primary construct.

The second attachment point can be a vertebra. The second attachmentpoint can be a pedicle, a transverse process, a lamina, a facet, aspinous process, or a vertebral body of the vertebra. The secondattachment point can be an implant implanted in any of the abovelocations. The vertebra can be inferior to the UIV of the primaryconstruct. The vertebra can be UIV, UIV−1, UIV−2, or lower. The secondattachment point can be a rib or other anatomical anchor point. Thesecond attachment point can be a bone structure. The second attachmentpoint can be a soft tissue structure. The second attachment point can bea muscle, a tendon, or a ligament. The extension can be attached to aplurality of the above-described second attachment points.

The extension can be attached to the second attachment point in any of avariety of ways. The extension can be attached to the second attachmentpoint using a suture, rivet, or staple. The extension can be attached tothe second attachment point using a clamp. The clamp can be attached toa lamina, spinous process, or other anatomical structure or implant. Theextension can be attached to the second attachment point using a hook.The hook can be hooked onto a lamina, spinous process, or otheranatomical structure or implant. The extension can be attached to thesecond attachment point using a bone anchor, e.g., a screw anchor, asuture anchor, an expandable anchor, a tether anchor, and/or asoft-tissue anchor, any of which may be of the type available from DEPUYSYNTHES of Raynham, Mass.

The second attachment point can be a spinal rod. The extension can beattached to the spinal rod using a clamp or connector that receives therod and the extension.

The second attachment point can be a bone anchor, e.g., a screw or ahook. The extension can be attached to the bone anchor using a clamp orconnector that receives the bone anchor and the extension. The extensioncan be clamped between a spinal rod and a rod seat of the bone anchor.The extension can be clamped between a spinal rod and a set screw orclosure mechanism of the bone anchor. The bone anchor can include afirst set screw or closure mechanism for locking the extension to thebone anchor and a second set screw or closure mechanism for locking aspinal rod to the bone anchor.

The above steps can be repeated to attach multiple extensions to thepatient's spine. The multiple extensions can share common attachmentpoints or can be attached at different locations. For example, first andsecond extensions can be placed in parallel on contralateral sides ofthe spinal midline. Inferior ends of the extensions can be attached torespective spinal rods and/or respective bone anchors of a primaryconstruct. Superior ends of the extensions can be attached to respectiveattachment points longitudinally offset from the primary construct, orto a common attachment point such as a spinous process of a superiorvertebra.

FIG. 3 illustrates an exemplary embodiment of an extension in the formof a connector 300 configured to be attached to a first attachment point(e.g., one or more spinous processes 302 of vertebrae superior to theprimary construct 200) and to a second attachment point (e.g., one ormore spinal rods 208 or bone anchors 210 of the primary construct).

As shown, the connector 300 can include a main body 304 with one or morearms 306 extending in a superior direction therefrom. The main body 304can be or can include a transverse cross-connector of the type known inthe art. Exemplary transverse cross-connectors are described in U.S.Pat. No. 7,717,938 entitled “DUAL ROD CROSS CONNECTORS AND INSERTERTOOLS”; U.S. Pat. No. 7,717,939 entitled “ROD ATTACHMENT FOR HEAD TOHEAD CROSS CONNECTOR”; and U.S. Pat. No. 8,361,117 entitled “SPINALCROSS CONNECTORS” each of which is hereby incorporated by referenceherein. The main body 304 can include any of the features of thecross-connectors described in the above patents. For example, the mainbody 304 can include one or more articulation joints to allow opposedrod connection points of the connector 300 to be movable relative to oneanother in one or more degrees of freedom. In the illustratedembodiment, the main body 304 includes a transverse strut 308 thatextends between opposed free ends along an axis A1. Each end of thestrut 308 can include a respective rod-receiving recess 310 and a setscrew for locking a spinal rod within the rod-receiving recess. Whilerod-receiving recesses are shown, it will be appreciated that variousother attachment features can be included instead or in addition. Forexample, one or both ends of the strut 308 can include an eyelet orother feature for attaching the strut directly to the head of a boneanchor 210.

The arms 306 can extend from the main body 304 in a superior direction.The arms 306 can extend along respective axes A2, A3. The arms 306 canbe straight or can be curved, bent, or stepped in one or more planes.For example, the arms 306 can be curved in the sagittal plane toapproximate a desired sagittal curvature of the patient's spine, or toexert extension forces on the patient's spine. The arms 306 can be rods,tubes, rails, and the like. The arms 306 can have a cross-section in aplane perpendicular to the arm axes A2, A3 that is cylindrical, oval,elliptical, square, or rectangular. The arms 306 be configured tofrictionally and/or mechanically engage the first attachment point,e.g., the one or more spinous processes 302. For example, the surface ofeach arm 306 adjacent to the spinous processes 302 can include teeth,ridges, roughening, or other surface features or finishes for grippingand engaging the spinous processes. As another example, the arms 306 canhave a geometry configured to wrap around a superior edge of the one ormore spinous processes 302. The arms 306 can be bent or curved, or caninclude protrusions, shoulders, or other features that wrap around thesuperior edge of the spinous process 302. The arms 306 can be shapedsuch that, when implanted in a patient, a first portion of each armcontacts a lateral surface of a spinous process and a second portion ofsaid arm contacts a superior surface of said spinous process.

The arms 306 can be less rigid than the spinal rod or rods 208 of theprimary construct 200. For example, the arms 306 can have a smallerdiameter or cross-section than the rods 208, and/or can be formed from adifferent material than the rods that is more flexible. The arms 306 canbe cut to length to extend to the desired vertebral level, or can beused with the off-the-shelf length. The illustrated arms 306 extend fromthe main body 304 to three vertebral levels superior to the UIV of theprimary construct 200. In other examples, the arms 306 can extend to onesuperior vertebral level, to two superior vertebral levels, or to morethan three superior vertebral levels.

In use, the primary construct 200 can be implanted through a primaryincision 212. The connector 300 can be inserted through the primaryincision 212 and the arms 306 can be tunneled beneath the patient's skinand/or soft tissue 214 in a superior direction from the primary incisionto the first attachment point. The arms 306 can be positioned oncontralateral sides of the spinal midline. The arms 306 can bepositioned such that they extend parallel to the rods 208 of the primaryconstruct 200 in the coronal plane. The main body 304 of the connector300 can be positioned such that it extends perpendicular to the rods 208of the primary construct 200 in the coronal plane and/or perpendicularto the spinal midline in the coronal plane. The arms 306 can bepositioned adjacent to or in contact with opposed lateral sides of thespinous processes 302 of one or more vertebrae superior to the UIV ofthe primary construct 200.

The arms 306 can be attached to the one or more spinous processes 302 bysuturing 312 as shown, or with a screw, rivet, hook, clamp, or otherattachment mechanism. The suture 312 or other attachment mechanism canextend transverse to the arms 306. The suture 312 or other attachmentmechanism can be inserted through the primary incision 212, tunneledsuperiorly beneath the patient's skin and/or soft tissue 214, andaffixed to the arms 306 and the spinous processes 302. A curved needle,a needle grasped with forceps, or other insertion instruments can beused to tunnel the suture 312 or other attachment mechanism. A superiorterminal end of the primary incision 212 can be inferior to the firstattachment point and/or inferior to the UIV of the primary construct200, and the suture 312 or other attachment mechanism can be appliedwithout extending the primary incision in the superior direction.Alternatively, or in addition, the suture 312 or other attachmentmechanism can be applied via one or more secondary incisions disposedsuperior to the primary incision 212. The secondary incisions can bepercutaneous or minimally-invasive incisions. The connector 300 can beinstalled as one piece or as separate components assembled in situ. Forexample, the arms 306 can be attached to the main body 304 while saidcomponents are disposed within the patient. A portion or the entirety ofthe connector 300 can be disposed superior to a superior terminal end ofthe primary incision 212 through which the primary construct 200 isimplanted.

FIG. 4 illustrates an exemplary embodiment of an extension in the formof a connector 400 configured to be attached to a first attachment point(e.g., one or more spinous processes 402 of vertebrae superior to theprimary construct 200) and to a second attachment point (e.g., one ormore spinal rods 208 or bone anchors 210 of the primary construct).Except as indicated below and as will be readily appreciated by onehaving ordinary skill in the art in view of the present disclosure, thestructure and operation of the connector 400 is the same as that of theconnector 300 described above.

The connector 400 can include adjustable arms 406 that are movablerelative to the main body 404 with one or more degrees of freedom. Forexample, the arms 406 can be slidably disposed in openings 414 formed inthe main body 404 such that the arms can translate relative to the mainbody along the axes A2, A3. The openings 414 can be oversized relativeto the exterior dimensions of the arms 406 to allow the arms to splaytowards or away from each other, e.g., to accommodate wider or narrowerspinous processes 402 therebetween, or to tilt in the sagittal plane,e.g., to adjust the attachment point along the height of the spinousprocesses 402. The connector 400 can include one or more lockingelements 416 for selectively locking the position and/or orientation ofthe arms 406 with respect to the main body 404. For example, the mainbody 404 can include threaded recesses that intersect the openings 414in which the arms 406 are slidably disposed. Set screws 416 can bethreaded into the recesses and tightened to clamp the arms 406 withinthe main body 404 and prevent movement between the arms and the mainbody. While independent set screws 416 are shown, in some arrangements asingle set screw can be used to simultaneously clamp both arms 406.Other locking mechanisms can be used instead or in addition to setscrews, such as cam locks, threaded nuts, and the like. The arms 406 caninclude one or more apertures 418. The arms 406 can include a pluralityof apertures 418 spaced along the length of the arms. The apertures 418can be sized to receive a suture, rivet, screw, or other fastener 412therethrough. The apertures 418 can be oriented perpendicular to theaxes A1, A2, and A3 as shown.

FIG. 5 illustrates an exemplary embodiment of an extension in the formof a connector 500 configured to be attached to a first attachment point(e.g., one or more spinous processes 502 of vertebrae superior to theprimary construct 200) and to a second attachment point (e.g., one ormore spinal rods 208 or bone anchors 210 of the primary construct).Except as indicated below and as will be readily appreciated by onehaving ordinary skill in the art in view of the present disclosure, thestructure and operation of the connector 500 is the same as that of theconnectors 300, 400 described above.

The arms 506 of the connector 500 can merge into a single arm as theyapproach the main body 504, forming a Y-shaped extension as shown. Thearms 506 can be positioned on opposite lateral sides of a spinousprocess 502 and a screw, rivet, or other fastener 520 can be insertedtherethrough to attach the arms to the spinous process. The arms 506 canbe flexible. The arms 506 can be configured to move away from oneanother as the connector 500 is advanced in a superior direction overthe spinous process 502 to allow the spinous process to enter a spacedefined between the arms. The arms 506 can be configured to then movetowards one another to capture the spinous process 502 therebetween. Thearms 506 can be configured to move further towards one another as thescrew, rivet, or other fastener 520 is applied to the connector 500. Thearms 506 can attach to a single spinous process 502 as shown or tomultiple spinous processes.

The arms 506 can have a geometry configured to wrap around a superioredge of the one or more spinous processes 502. The arms 506 can be bentor curved, or can include protrusions, shoulders, or other features 522that wrap around the superior edge of the spinous processes 502. Thearms 506 can be shaped such that, when implanted in a patient, a firstportion of each arm contacts a lateral surface of a spinous process anda second portion of said arm contacts a superior surface of said spinousprocess.

FIG. 6 illustrates an exemplary embodiment of an extension in the formof a connector 600 configured to be attached to a first attachment point(e.g., one or more spinous processes 602 of vertebrae superior to theprimary construct 200) and to a second attachment point (e.g., one ormore spinal rods 208 or bone anchors 210 of the primary construct).Except as indicated below and as will be readily appreciated by onehaving ordinary skill in the art in view of the present disclosure, thestructure and operation of the connector 600 is the same as that of theconnectors 300, 400, 500 described above.

The connector 600 can include a rotatable or slidable ring or collar 624through which the arms 606 extend. The collar 624 can be rotatablerelative to the arms 606 about an axis A4 that is perpendicular to theaxis A1 in the coronal plane and parallel or substantially parallel tothe axes A2, A3 in the coronal plane. A central opening of the collar624 can include an interior thread that interfaces with an exteriorthread formed on the arms 606. The threads of the collar 624 and/or thethreads of the arms 606 can be tapered such that rotating the collar ina first direction squeezes the arms towards one another, e.g., to clamponto a spinous process 602 disposed between the arms, and rotation ofthe collar in a second, opposite direction allows the arms to move awayfrom each other, e.g., to release from a spinous process disposedbetween the arms. Interior surfaces of the arms 606 can include teeth,spikes, or other surface features or treatments for biting into thespinous processes 602 and enhancing the grip on the spinous processes.The arms 606 can be resilient or can be otherwise biased towards thereleased position. In other arrangements, the collar 624 can be slidablydisposed over the arms 606 and can be configured to translate relativethereto along the axis A4, with or without rotating the collar relativeto the arms. The collar 624 and/or the arms 606 can be tapered such thatsliding the collar in the superior direction relative to the arms causesthe arms to move towards each other and sliding the collar in theinferior direction relative to the arms allows the arms to move awayfrom each other. The arms 606 can attach to multiple spinous processes602 as shown or to a single spinous process.

In use, the connector 600 can be inserted through the primary incisionused to implant the primary construct 200. The opposed arms 606 can betunneled in a superior direction and positioned on opposite lateralsides of one or more spinous processes 602 of vertebrae superior to theUIV of the primary construct 200. The collar 624 can then be rotated orslid relative to the arms 606 to move the arms towards one another andclamp the arms onto the one or more spinous processes. The main body 604of the connector can be attached to the primary construct 200, e.g., byclamping onto one or more rods 208 of the primary construct.

While the connectors 300, 400, 500, 600 above are shown with a main bodyhaving a rod-to-rod connection, it will be appreciated that otherarrangements can be used instead or in addition. For example, any of theconnectors described herein can include a main body configured forattachment directly to first and second bone anchors, such as pedicle orlateral mass screws, of the primary construct. FIG. 7 illustrates anexemplary connector 700 that is similar to the connector 600 describedabove, but includes a main body 704 with opposed eyelets 726. Theeyelets 726 can be configured to attach to respective bone anchors. Forexample, each eyelet 726 can receive a threaded post that extendsproximally from a bone anchor, and a nut can be advanced over thethreaded post to secure the main body 704 to the bone anchor. Theeyelets 726 can be formed in washers 728, which can be movably coupledto the main body 704. For example, the washers 728 can be slidable alongthe axis Al relative to the main body 704.

The connectors 300, 400, 500, 600 above can be rigidly attached to theprimary construct 200, or can be flexibly attached thereto. For example,any of the connectors described herein can include a main body withapertures or other features for attaching the main body to the primaryconstruct using one or more flexible tethers or other linkages. FIG. 8illustrates an exemplary connector 800 that is similar to the connector600 described above, but includes a main body 804 with opposed apertures830 for receiving one or more flexible tethers, which can in turn beclamped or otherwise attached to the primary construct 200. Theconnector 800 can include screws or other locking elements 832 forclamping onto a tether extending through the apertures 830. In onearrangement, a single tether can be attached to a first spinal rod ofthe primary construct 200, extend superiorly to the connector 800, passthrough both apertures 830 of the connector, and return inferiorly toattach to a second contralateral spinal rod of the primary construct. Inanother arrangement, a first tether can be attached to a first spinalrod of the primary construct 200, extend superiorly to the connector800, and attach to a first aperture 830 of the connector. A secondtether can be attached to a second contralateral spinal rod of theprimary construct 200, extend superiorly to the connector 800, andattach to a second aperture 830 of the connector.

The connectors disclosed herein can be implanted by inserting theconnector through a primary incision through which the primary constructis implanted, and then tunneling the arms of the connector throughtunnels formed alongside or towards the first attachment point(s), e.g.,one or more spinous processes of superior vertebrae. The tunnels can beformed beneath the skin and/or soft tissue of the patient. The tunnelscan be formed in a muscle-sparing fashion. A fastener used to attach thearms to the first attachment point(s) can be applied through the sametunnels or through a separate tunnel. An instrument for applying thefastener can be inserted through the same tunnels or through a separatetunnel. These techniques can be used to reduce the number of incisionsand the amount of tissue disruption associated with placing theconstruct and the connector, which can help prevent PJK/PJF.

In an exemplary arrangement, an insertion jig can be attached to theconnector and can be rotated about the attachment point to guide arivet, suture, needle, screw, or other fastener through an arc thatintersects a predetermined target location along the arms of theconnector. The insertion jig can thereby consistently and accuratelyguide the fastener to the desired location, even when the desiredlocation is not visible because it is beneath the skin and/or softtissue of the patient. The insertion jig can be detached from theconnector and removed prior to closing the patient.

In another exemplary arrangement, the connector can define a groove,track, or ridge for guiding a rivet, suture, needle, screw, or otherfastener to a predetermined target location along the arms of theconnector. An inserter instrument, such as a riveting tool, can beguided along the groove, track, or ridge to align the operating end ofthe instrument with the desired location for applying the fastener. Thearms of the connector can have an I-beam cross-section, or can otherwiseinclude a guide track through which an instrument can be guided to applya fastener in the desired location.

FIG. 9 illustrates an exemplary connector 900 having guide tracks formedin or on the arms 906 of the connector. As shown, one or both arms 906can include a guide track 934 formed in or on a posterior face of thearm. The guide track 934 can extend in a caudal-to-cranial direction.The guide track 934 can be a groove, recess, track, ridge, and/orprotrusion formed on the arm 906. The guide track 934 can have arectangular transverse cross section. The guide track 934 can be formedin the center or substantially in the center of the posterior surface ofthe arm 906. While the illustrated connector 900 is similar to theconnector 400 described above, it will be appreciated that any of theconnectors herein can include similar guide tracks.

FIG. 10 illustrates an exemplary connector 1000 having guide tracksformed in or on the arms 1006 of the connector. As shown, one or botharms 1006 can include a guide track 1034 formed in or on a posteriorface of the arm. The guide track 1034 can extend in a caudal-to-cranialdirection. The guide track 1034 can be a groove, recess, track, ridge,and/or protrusion formed on the arm 1006. The guide track 1034 can havea dovetail transverse cross section. For example, the guide track 1034can be a protrusion that extends posteriorly from a posterior surface ofthe arm 1006, the protrusion having opposed lateral sidewalls that taperobliquely towards one another in a posterior-to-anterior direction.Instruments guided by the guide track 1034 can include a counterpartdovetail groove for mating with the guide track, which can facilitateretention of the instrument to the guide track. The guide track 1034 canbe formed in the center or substantially in the center of the posteriorsurface of the arm 1006. While a male dovetail feature is shown, thearms 1006 can instead include a female dovetail feature configured toreceive a male dovetail feature of an instrument. While the illustratedconnector 1000 is similar to the connector 400 described above, it willbe appreciated that any of the connectors herein can include similarguide tracks.

FIG. 11 illustrates an exemplary connector 1100 having guide tracksformed in or on the arms 1106 of the connector. As shown, one or botharms 1106 can include a guide track 1134 formed in or on a lateral faceof the arm. The guide track 1134 can extend in a caudal-to-cranialdirection. The guide track 1134 can be a groove, recess, track, ridge,and/or protrusion formed on the arm 1106. The guide track 1134 can havea dovetail transverse cross section. For example, the guide track 1134can be a recess that extends inward from a lateral surface of the arm1106, the recess having opposed anterior and posterior sidewalls thattaper obliquely towards one another in a medial-to-lateral direction.Instruments guided by the guide track 1134 can include a counterpartdovetail protrusion for mating with the guide track, which canfacilitate retention of the instrument to the guide track. The guidetrack 1134 can be formed in the center or substantially in the center ofthe lateral surface of the arm 1106. While a female dovetail feature isshown, the arms 1106 can instead include a male dovetail featureconfigured to be receive in a female dovetail feature of an instrument.While the illustrated connector 1100 is similar to the connector 400described above, it will be appreciated that any of the connectorsherein can include similar guide tracks.

FIG. 12 illustrates an exemplary connector 1200 having guide tracksformed in or on the arms 1206 of the connector. As shown, one or botharms 1206 can include a guide track 1234 formed therein or thereon. Theguide track 1234 can extend in a posterior-to-anterior direction. Theguide track 1234 can be a groove, recess, track, ridge, and/orprotrusion formed on the arm 1206. The guide track 1234 can have adovetail transverse cross section. Instruments guided by the guide track1234 can include a counterpart dovetail feature for mating with theguide track, which can facilitate retention of the instrument to theguide track. The guide track 1234 can be formed in the center orsubstantially in the center of the arm 1206. While the illustratedconnector 1200 is similar to the connector 500 described above, it willbe appreciated that any of the connectors herein can include similarguide tracks.

It should be noted that any ordering of method steps expressed orimplied in the description above or in the accompanying drawings is notto be construed as limiting the disclosed methods to performing thesteps in that order. Rather, the various steps of each of the methodsdisclosed herein can be performed in any of a variety of sequences. Inaddition, as the described methods are merely exemplary embodiments,various other methods that include additional steps or include fewersteps are also within the scope of the present disclosure.

While extension of a construct in a superior direction is generallydescribed above, it will be appreciated that the systems and methodsdisclosed herein can also be used to extend a construct in an inferiordirection, or solely within the superior and inferior limits of aprimary construct, e.g., to reinforce the primary construct.

While the systems and methods disclosed herein are generally describedin the context of spinal surgery with rigid spinal fixation constructs,it will be appreciated that the systems and methods herein can be usedwith various other types of fixation or stabilization hardware, in anybone, in non-bone tissue, or in non-living or non-tissue objects. Thesystems disclosed herein and the various component parts thereof can befully implanted, or can be used as part of an external fixation orstabilization system. The systems and methods disclosed herein can beused in minimally-invasive surgery and/or open surgery.

The systems disclosed herein and the various component parts thereof canbe constructed from any of a variety of known materials. Exemplarymaterials include those which are suitable for use in surgicalapplications, including metals such as stainless steel, titanium,cobalt-chromium, titanium-molybdenum, or alloys thereof, polymers suchas PEEK, ceramics, carbon fiber, and so forth. The various components ofthe systems disclosed herein can be rigid or flexible. One or morecomponents or portions of the system can be formed from a radiopaquematerial to facilitate visualization under fluoroscopy and other imagingtechniques, or from a radiolucent material so as not to interfere withvisualization of other structures. Exemplary radiolucent materialsinclude carbon fiber and high-strength polymers.

Although specific embodiments are described above, it should beunderstood that numerous changes may be made within the spirit and scopeof the concepts described.

1. A surgical method comprising: attaching a primary construct to aspine of a patient, the primary construct extending between an uppermostinstrumented vertebra (UIV) and a lowermost instrumented vertebra (LIV);attaching a connector to a first attachment point, the first attachmentpoint comprising a spinous process disposed superior to the UIV of theprimary construct; positioning the connector relative to the patient'sspine; and attaching the connector to a second attachment point, thesecond attachment point being disposed at or inferior to the UIV of theprimary construct.
 2. The method of claim 1, wherein the firstattachment point comprises a plurality of spinous processes disposedsuperior to the UIV of the primary construct.
 3. The method of claim 1,wherein the second attachment point comprises first and second spinalrods of the primary construct.
 4. The method of claim 1, wherein thesecond attachment point comprises first and second bone anchors of theprimary construct.
 5. The method of claim 1, wherein the connectorincludes a main body with first and second arms extending in a superiordirection therefrom.
 6. The method of claim 5, wherein attaching theconnector to the second attachment point comprises attaching opposedconnection points of the main body to contralateral components of theprimary construct.
 7. The method of claim 5, wherein the arms are curvedin the sagittal plane and apply extension forces to the patient's spine.8. The method of claim 5, wherein attaching the connector to the firstattachment point comprises urging teeth formed on the arms intoengagement with the spinous process.
 9. The method of claim 5, whereinattaching the connector to the first attachment point comprisespositioning first portions of each arm in contact with respectivelateral surfaces of the spinous process and positioning second portionsof each arm in contact with a superior surface of the spinous process.10. The method of claim 5, wherein attaching the connector to the firstattachment point comprises suturing or riveting the arms of theconnector to the spinous process.
 11. The method of claim 5, whereinattaching the connector to the first attachment point comprises applyingsutures through apertures formed in the arms.
 12. The method of claim 5,wherein positioning the connector relative to the patient's spinecomprises at least one of: (i) longitudinally translating the armsrelative to the main body within recesses formed in the main body and(ii) tilting the arms relative to the main body within recesses formedin the main body.
 13. The method of claim 5, wherein positioning theconnector relative to the patient's spine comprises tightening a lockingmechanism of the connector to lock a position and/or orientation of thearms relative to the main body.
 14. The method of claim 5, whereinpositioning the connector comprises spreading the arms of the connectorapart from one another to allow the spinous process to be insertedtherebetween and then returning the arms towards one another to capturethe spinous process within a space defined between the arms.
 15. Themethod of claim 5, wherein attaching the connector to the firstattachment point comprises rotating or sliding a collar with respect tothe arms of the connector to clamp the arms onto the spinous process.16. The method of claim 5, wherein the arms have a stiffness that isgreater than a stiffness of patient anatomy superior to the UIV of theprimary construct and that is less than a stiffness of the primaryconstruct.
 17. The method of claim 5, wherein the arms have a degree ofspinal motion restriction that is greater than that of patient anatomysuperior to the UIV of the primary construct and less than that of theprimary construct.
 18. The method of claim 5, wherein the arms limitflexion of the spine without completely preventing such flexion.
 19. Themethod of claim 1, wherein the primary construct is implanted through aprimary incision and wherein the connector is positioned relative to thepatient's spine and attached to the first and second attachment pointsthrough the primary incision.
 20. The method of claim 19, wherein theprimary incision has a superior terminal end that is disposed at orinferior to the UIV of the primary construct.
 21. The method of claim19, wherein positioning the connector relative to the patient's spinecomprises tunneling first and second arms of the connector in a superiordirection from the primary incision to position the arms alongside aplurality of spinous processes disposed superior to a superior terminalend of the primary incision.
 22. The method of claim 1, whereinattaching the connector to the second attachment point comprisesthreading an elongate flexible tether through one or more apertures ofthe connector and attaching the tether to the primary construct.
 23. Themethod of claim 1, wherein vertebrae instrumented with the primaryconstruct are fused to one another or prepared for such fusion andvertebrae to which the primary construct is extended by the connectorare not fused or prepared for fusion.
 24. The method of claim 1, whereinthe primary construct comprises a rigid spinal rod attached to first andsecond vertebrae by respective bone anchors.
 25. The method of claim 1,wherein no portion of the connector is disposed anterior to any laminaof the patient's spine when the connector is attached to the first andsecond attachment points.
 26. A surgical system, comprising: a primaryconstruct comprising a rigid spinal fixation rod and first and secondbone anchors configured to attach the spinal rod to first and secondvertebrae; and a connector comprising: a main body having at least oneattachment point for attaching the connector to the primary construct;and first and second arms extending in a superior direction from themain body.
 27. The system of claim 26, wherein the at least oneattachment point comprises first and second rod receiving recessesdisposed at opposite ends of the main body, and wherein the main bodyincludes a transverse strut extending between the first and second rodreceiving recesses, and wherein the first and second arms extendsuperiorly from the transverse strut.
 28. The system of claim 26,wherein the arms include bone engaging teeth or surface features formedthereon.
 29. The system of claim 26, wherein the arms are shaped to wraparound the superior edge of a spinous process.
 30. The system of claim26, wherein the arms are shaped to simultaneously contact a lateralsurface of a spinous process and a superior surface of said spinousprocess.
 31. The system of claim 26, wherein the arms are selectivelytranslatable and/or rotatable relative to the main body.
 32. The systemof claim 26, wherein the main body includes a locking mechanismconfigured to lock a position and/or orientation of the arms relative tothe main body.
 33. The system of claim 26, wherein the arms are moreflexible than the spinal rod.
 34. The system of claim 26, wherein thearms extend superiorly from the main body by a length of at least twovertebral levels of an adult human patient.
 35. The system of claim 26,wherein the arms include apertures for receiving a fastenertherethrough.
 36. The system of claim 26, wherein the arms merge into asingle arm as they approach the main body.
 37. The system of claim 26,further comprising a collar that is rotatable and/or slidable relativeto the arms to move the arms towards one another.
 38. The system ofclaim 37, wherein the collar includes an interior thread engaged with anexterior thread of the arms, at least one of the interior and exteriorthreads being tapered.
 39. The system of claim 26, further comprising anelongate flexible tether insertable through one or more openings formedin the main body of the connector.
 40. The system of claim 39, whereinthe main body includes one or more locking elements configured to clamponto the tether when the tether is disposed through the one or moreopenings.